Hypofractionated SBRT For Prostate Cancer

Prospective Evaluation Of Hypofractionated Stereotactic Body Radiotherapy For Low And Intermediate Risk Prostate Cancer

The purpose of this study is to determine, in both low-risk and intermediate-risk cohorts, the rates of acute and late grade 3 or higher gastrointestinal and genitourinary toxicity observed during a 24 month follow up and to estimate the rate of biochemical Disease-Free Survival, Phoenix and American Society for Therapeutic Radiology and Oncology definitions, at 2 years following hypofractionated stereotactic body radiation therapy for low and intermediate risk prostate cancer.

Radiosurgery should be ideal for treating prostate cancer because:

• targeting accuracy for static targets is excellent, with an error of about 1mm,
• it can adjust for intra-fractional organ motion, reducing the volume of the target PTV and therefore the dose to surrounding organs,
• by using over one-hundred non-conplanar beams, the dose gradient between the prostate and surrounding tissues may be superior to that achieved with conventional linear accelerators,
• the radiobiology of prostate cancer may favor large dose per fractions.

Inclusion Criteria:

• Histologically proven prostate adenocarcinoma
• Gleason score 2-7
• Biopsy within one year of date of registration
• Clinical stage T1b-T2b, N0-Nx, M0-Mx (AJCC 6th Edition)
• T-stage and N-stage determined by physical exam and available imaging studies (ultrasound, CT, and/or MRI)
• M-stage determined by physical exam, CT or MRI. Bone scan not required unless clinical findings suggest possible osseous metastases.
• PSA ≤ 20 ng/dL
• Patients belonging in one of the following risk groups:
• Low: CS T1b-T2a and Gleason 2-6 and PSA ≤ 10, or
• Intermediate: CS T2b and Gleason 2-6 and PSA ≤ 10, or CS T1b-T2b, and Gleason 2-6 and PSA ≤ 20 ng/dL, or Gleason 7 and PSA ≤ 10 ng/dL
• Prostate volume: ≤ 100 cc
• Determined using: volume = π/6 x length x height x width
• Measurement from CT or ultrasound ≤90 days prior to registration.
• ECOG performance status 0-1
• Completion of patient questionnaires:FACT-G questionnaire, AUA questionnaire, EPIC-26 questionnaire, SHIM questionnaire, Utilization of Sexual Medications/Devices questionnaire
• Consent signed.

Exclusion Criteria:

• Prior prostatectomy or cryotherapy of the prostate
• Prior radiotherapy to the prostate or lower pelvis
• Implanted hardware or other material that would prohibit appropriate treatment planning or treatment delivery, in the investigator's opinion.
• Chemotherapy for a malignancy in the last 5 years.
• History of an invasive malignancy (other than this prostate cancer, or basal or squamous skin cancers) in the last 5 years.
• Hormone ablation for two months prior to enrollment, or during treat